21113231100 has 144 divisors (see below), whose sum is σ = 65844639840. Its totient is φ = 5192524800.

The previous prime is 21113231077. The next prime is 21113231147. The reversal of 21113231100 is 113231112.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 21113231100.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 7256446 + ... + 7259354.

Almost surely, 2^21113231100 is an apocalyptic number.

21113231100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21113231100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32922319920).

21113231100 is an abundant number, since it is smaller than the sum of its proper divisors (44731408740).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21113231100 is a wasteful number, since it uses less digits than its factorization.

21113231100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4800 (or 4793 counting only the distinct ones).

The product of its (nonzero) digits is 36, while the sum is 15.

Adding to 21113231100 its reverse (113231112), we get a palindrome (21226462212).

The spelling of 21113231100 in words is "twenty-one billion, one hundred thirteen million, two hundred thirty-one thousand, one hundred".